My definition of collection is broad, as in it's just whatever I want it to be. Displaying collections doesn't have to mean that you have every piece of china or a full set of anything. For me displaying a collection can be as simple as grouping together things that tell a story, or even things that are visually interesting when seen en masse, like the numbered napkin rings in the black and white bowl, above. The shelf below holds items related to a trip to the Baltic capitals. And in case you are wondering Elizabeth Gilbert's, Eat, Pray, Love belongs everywhere. All the time.
The collection of nudes sketched by my son, was carefully put together. There were lots of others but I chose ones where the position of the bodies and the discreetness was similar in all of them. There is something so coherent about these particular ones.
Travel stories told by collections of objects include a stack of Mexican blankets and a stack of travel related treasures.
My camera collection in a bamboo basket that my grandfather brought home from Papua, New Guinea where he was a missionary in the 1960s.
A collection is never something that I'm using for any other purpose than it just makes sense for some things to be viewed together, like the cameras. Other times things that seemingly have no connection are pleasing to the eye, and sometimes putting things together allows them to tell a story about the family that lives in your home.